Possible backdoor in ftpd?

[jseng () darwin technet sg (James Seng)]

I have recieve this log from my xferlog from my ftpsite.

Mon Feb  6 22:59:03 1995 1 merlion.singnet.com.sg 9 /incoming/cr b _ i a 
brains@ ftp 0 *
Mon Feb  6 22:59:59 1995 1 merlion.singnet.com.sg 9 /incoming/cr b _ i a 
brains@ ftp 0 *

What he basically does is that he has uploaded a file called 'cr' (9 
bytes) in binary mode into my ftp.technet.sg:/incoming directory. It is 
nothing of interested except that the file he uploaded (cr) contain

chroot /

I suspect it has do to with the backdoor in the trojan wu-ftpd which 
happen to be distributed with bsdi (yea..mine is a bsdi but with a 
patched ftpd). Anyone has more information on this?

-James Seng